--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/pk/pkcs1/pkcs_1_v15_sa_encode.c	Fri May 06 13:23:02 2005 +0000
@@ -0,0 +1,84 @@
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, [email protected], http://libtomcrypt.org
+ */
+#include "tomcrypt.h"
+
+/** 
+  @file pkcs_1_v15_sa_encode.c
+  PKCS #1 v1.5 Signature Padding, Tom St Denis 
+*/
+
+#ifdef PKCS_1
+
+/**
+  Perform PKCS #1 v1.5 Signature Padding
+  @param msghash         The hash you wish to incorporate in the padding
+  @param msghashlen      The length of the hash
+  @param hash_idx        The index of the hash used
+  @param modulus_bitlen  The length of the RSA modulus that will sign this (bits)
+  @param out             [out] Where to store the padded data
+  @param outlen          [in/out] Max size and resulting size of the padded data
+  @return CRYPT_OK if successful
+*/
+int pkcs_1_v15_sa_encode(const unsigned char *msghash,  unsigned long msghashlen,
+                               int            hash_idx, unsigned long modulus_bitlen,
+                               unsigned char *out,      unsigned long *outlen)
+{
+  unsigned long derlen, modulus_bytelen, x, y;
+  int err;
+
+  LTC_ARGCHK(msghash != NULL)
+  LTC_ARGCHK(out     != NULL);
+  LTC_ARGCHK(outlen  != NULL);
+
+  if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) {
+     return err;
+  }
+
+  /* hack, to detect any hash without a DER OID */
+  if (hash_descriptor[hash_idx].DERlen == 0) {
+     return CRYPT_INVALID_ARG; 
+  }
+
+  /* get modulus len */
+  modulus_bytelen = (modulus_bitlen>>3) + (modulus_bitlen & 7 ? 1 : 0);
+
+  /* get der len ok?  Forgive my lame German accent.... */
+  derlen = hash_descriptor[hash_idx].DERlen;
+
+  /* valid sizes? */
+  if (msghashlen + 3 + derlen > modulus_bytelen) {
+     return CRYPT_PK_INVALID_SIZE;
+  }
+
+  if (*outlen < modulus_bytelen) {
+     return CRYPT_BUFFER_OVERFLOW;
+  }
+
+  /* packet is 0x00 0x01 PS 0x00 T, where PS == 0xFF repeated modulus_bytelen - 3 - derlen - msghashlen times, T == DER || hash */
+  x = 0;
+  out[x++] = 0x00;
+  out[x++] = 0x01;
+  for (y = 0; y < (modulus_bytelen - 3 - derlen - msghashlen); y++) {
+     out[x++] = 0xFF;
+  }
+  out[x++] = 0x00;
+  for (y = 0; y < derlen; y++) {
+     out[x++] = hash_descriptor[hash_idx].DER[y];
+  }
+  for (y = 0; y < msghashlen; y++) {
+     out[x++] = msghash[y];
+  }
+
+  *outlen = modulus_bytelen;
+  return CRYPT_OK;
+}
+
+#endif /* PKCS_1 */